Reduction of hydrogen sulfide and/or malodor gassing from water via the addition of peroxyacetic acid/hydrogen peroxide product

ABSTRACT

The invention provides methods and compositions for reducing the malodorous sulfide gas released by a wastewater treatment system. The method preserves the vitality of waste consuming organisms within the system. The method comprises the steps of: determining the SRP PAA demand of the system, determining the aerobic PAA demand of the system, and adding a composition in an amount such that it is in excess of the SRP PAA demand but is below the aerobic PAA demand. Even though the composition increases the amount of sulfates within the wastewater it reduces the amount of SRP which prevents the malodorous sulfite gas release. The composition comprises at least one percarboxyacid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from provisional application 62/043,559filed on Aug. 29, 2014 and is a Continuation in part of U.S. patentapplication Ser. No. 13/891,908 filed on May 10, 2013 now U.S. Pat. No.8,992,780.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

The invention relates to compositions, methods, and apparatuses forreducing the release of malodorous sulfide gases from water sources.Sulfide gases such as but not limited to DMDS and hydrogen sulfide aremalodorous gases whose presence in populated areas are often perceivedof as an irritating nuisance. In addition sulfide gases can beexplosive, corrosive, and hazardous to health. Most pernicious of all,prolonged contact to sulfide gases can anesthetize one's sense of smellcausing the loss of one's ability to detect the presence of other moretoxic gases.

This problem is particularly acute when dealing with expelled water fromthe food processing industry. The food processing industry employs vastquantities of water to create purified food products. Among the foodindustries with high volumes of water requirements are the sugar caneprocessing, sugar beet processing, fruit and vegetable processing, meatand poultry processing, grain processing, fat and oil processing, anddairy product processing industries. Unit operations that are mostcommon to the various types of food processing listed above includeenergy transfer systems, including boiler systems.

In food industries such as the sugar industry, the condensate releasedby a multiple effect evaporator (“MEE”) is an example of a typicalexpelled fluid. MEE often becomes contaminated and must be disposed ofas wastewater. Examples of these contaminating events include steamcarry-over, foaming induced by MEE control issues, leaking of sugar thinjuice into the stream, or other causes. Contamination is generallycomprised of organic salts, inorganic salts, and sucrose. These eventsare more likely to happen during operation upsets and can cause “sugarshot” (a sudden spike in sugar dosage/concentration in the processfluid). Sugar shots pose particular problems with wastewater disposal asthey result in wild variations in microorganisms' populations,diversity, activity, and waste processing capabilities. These wildvariations complicate the process of odor management in wastewater.

Unfortunately as described for example in U.S. Pat. No. 7,160,712,malodorous sulfide gases are a common byproduct of waste watertreatment. In wastewater treatment microorganisms are used to break downorganic (waste) material. Microorganisms accomplish this by utilizingoxygen to oxidize the material as a part of their metabolic functions.Because of its efficiency in microorganism's metabolisms, whenavailable, microorganisms will preferably utilize aerobic processeswhich require molecular oxygen. When molecular oxygen is less thanoptimally available, some microorganisms will use anaerobic processeswhich use other compounds such as nitrates and sulfates. Becausenitrates afford superior metabolic efficiency when compared to sulfates,organisms will only use sulfates for oxidation when both nitrates andmolecular oxygen are less than optimally available. Sulfate oxidationproduces sulfide gases.

Not all organisms are capable or are as capable of utilizing sulfates tometabolize organic material. Organisms that are highly effective atoxidizing or reducing sulfur bearing species (such as sulfates,thiosulfates, and elemental sulfur) are known as SRP (sulfur reducingprokaryotes). A profusion of SRP in a water sample will often result inhigh releases of sulfide gases. In addition, as SRP proliferate, theytend to strip water supplies of all their oxygen content resulting inhighly anaerobic conditions. Once the water becomes anaerobic, theability of microorganisms to break down organic material drasticallyslows. As a result a number of legal jurisdictions prohibit thedischarge of treated water that contains too little dissolved oxygen.Thus SRP profusion is both a nuisance and makes water disposaldifficult.

A number of prior art strategies have been proposed to address therelease of sulfide gas. One approach is sulfide scavenging. In sulfidescavenging chemicals are applied to the water which reacts with andtraps the sulfide gas before it vaporizes out of the liquid medium. Asdescribed in Published US Patent Applications 2012/0012507,2012/0012506, 2012/0329930, 2012/0067782, 2009/0242461, and EuropeanPatent Application EP 0 882 778 A2, scavengers include but are notlimited to chlorine, bleach, hydrogen peroxide, potassium permanganate,ferric chloride, hydrogen sulfide, glyoxal, glyoxal-polyamines,alpha-amino ethers, polyaliphatic amines, alkyl-triazines, andnitroxides. Another strategy is sulfate substitution which involvesfeeding molecular oxygen or nitrates into the water to displace sulfatesfrom being metabolized. And a third strategy as described in U.S. Pat.No. 6,015,536 is to treat the gaseous effluent itself to remove thesulfides.

Unfortunately all of these prior approaches are excessively complex,costly, unreliable, and/or are otherwise unsatisfactory. As a resultthere remains a clear utility in improved compositions, methods, andapparatuses for reducing the release of malodorous sulfide gases fromwater sources. The art described in this section is not intended toconstitute an admission that any patent, publication or otherinformation referred to herein is “prior art” with respect to thisinvention, unless specifically designated as such. In addition, thissection should not be construed to mean that a search has been made orthat no other pertinent information as defined in 37 CFR §1.56(a)exists.

BRIEF SUMMARY OF THE INVENTION

At least one embodiment of the invention is directed towards a method ofreducing the odor released by a wastewater treatment system whilepreserving the vitality of waste consuming organisms within the system.The method comprises the steps of: continuously adding to a process flowof water a composition in an amount such that it is in excess of the SRPPAA demand but is below the aerobic PAA demand, detecting a sudden surgein nutrient content in the process flow of water, and in response to thedetected surge adding an effective amount of Fenton's Reagent to theflow. The composition comprises at least one peroxy acid.

The Fenton's Reagent may be added before there is a detectable change inthe population of microorganisms in the wastewater treatment system. TheFenton's Reagent may be added before the nutrient surge reaches thewastewater treatment system. The Fenton's Reagent may be added afterthere is a noticeable increase in odor. The amount of continuously addedcomposition might not be altered in response to the sudden surge innutrient content. The surge in nutrient content may be detected bymeasuring fluorescence from the nutrient. The surge in nutrient contentmight be detected by measuring fluorescence from the nutrient inresponse to a first excitation light source having a wavelength of 320nm and a second excitation light source having a wavelength of 406 nm.

The nutrient might be one or more sugars. The process flow might becondensate from a boiler in a sugar mill. The composition mighteliminate at least one biofilm layer on at least one surface of thewastewater treatment system and the lack of said biofilm layer mightprevent the localization against that surface of at least one of: H₂S, abiogenic acid, a corrosive biogenic material, and any combinationthereof. The composition might comprise PAA.

The composition may be added in an amount lower than a quaternaryammonium odor suppressant but is more than 10% effective than saidquaternary ammonium odor suppressant would be at suppressing sulfideodor release. The aerobic PAA demand of the system may be determined bymeasuring the minimum ppm amount of composition that needs to be addedto cause substantially no less than a 98% drop in total active ATP inthe wastewater. The method might exclude the presence of an odorsuppressing co-ingredient which neutralizes the innate odor of theperoxy acid. The composition might be fed directly into a portion of thewastewater system selected from the group consisting of: a wastewaterpond, an EQ tank, a wastewater storage tank, and any combinationthereof. The composition might be fed directly into one item selectedfrom the group consisting of: a trunk line which feeds wastewater into astorage vessel, a stationary water system, a recirculating water system,and any combination thereof. The composition may be fed directly into acovered pond and the composition reduces the amount of sulfide acidcorrosion by more than 10% than if the composition were not added to thepond. The composition may reduce oxygen demand of the wastewater. Theperacid may be a reaction between a peroxygen source other than hydrogenperoxide with peracetic acid.

Additional features and advantages are described herein, and will beapparent from, the following Detailed Description.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the invention is hereafter described withspecific reference being made to the drawings in which:

FIG. 1 is a graph demonstrating that the substantial elimination of odorwhen measured according to a smell test can occur without completelyeliminating all microorganisms in a system.

FIG. 2 is a graph demonstrating that adding small dosages of one or moreperacids to a waters system eliminates aerobic microorganisms and SRPdifferently over time.

FIG. 3 is a graph demonstrating the use of the invention to address odorcontrol in wastewater streams susceptible to sugar shock/nutrient shock.

For the purposes of this disclosure, like reference numerals in thefigures shall refer to like features unless otherwise indicated. Thedrawings are only an exemplification of the principles of the inventionand are not intended to limit the invention to the particularembodiments illustrated.

DETAILED DESCRIPTION OF THE INVENTION

The following definitions are provided to determine how terms used inthis application, and in particular how the claims, are to be construed.The organization of the definitions is for convenience only and is notintended to limit any of the definitions to any particular category.

“Fenton's Reagent” means a composition of matter in which hydrogenperoxide and ferrous iron (Fe(II)(+2 valence state)) are in such amountsand under such conditions that hydroxyl radicals, hydroxyl ions, andferric iron (Fe(III)(+3 valence state)) form or have formed and then atleast some react or have reacted to form a superoxide, a proton, andreverts or has reverted the ferric iron back into ferrous iron, it canbe characterized as occurring according to the equations:Fe²⁺+H₂O₂→Fe³⁺+HO.+OH⁻  (1)Fe³⁺+H₂O₂→Fe²⁺+HOO.+H⁺  (2)In addition a number of secondary and subsequent reactions may occurinvolving any one, some, or all of these products, reactants, andderivatives thereof, further details regarding Fenton's Reagent and itssubsequent reactions are provided in the references: Fenton Reaction,Controversy Concerning the Chemistry, by K Barbusinski, EcologicalChemistry and Engineering, Vol. 16, No. 3 pp. 347-358, (2009), Fenton'sReagent Revisited, by Cheves Walling, Accounts of Chemical Research,vol. 8, pp. 125-131 (1975), and Hydrogen Peroxide Catalytic Oxidation ofRefractory Organics in Municipal Waste Waters, by D Bishop et al, Ind.Eng. Chem., Process Design & Development, vol. 7, pp. 1110-117 (1968).

“Consisting Essentially of” means that the methods and compositions mayinclude additional steps, components, ingredients or the like, but onlyif the additional steps, components and/or ingredients do not materiallyalter the basic and novel characteristics of the claimed methods andcompositions.

“Microorganism” means any noncellular or unicellular (includingcolonial) organism. Microorganisms include all prokaryotes.Microorganisms include bacteria (including cyanobacteria), Archaea(including sulfate-reducing Archaea), spores, lichens, fungi, molds,protozoa, virinos, viroids, viruses, phages, and some algae. As usedherein, the term “microbe” is synonymous with microorganism.

“Mixed” or “mixture” when used relating to “peroxycarboxylic acidcomposition” or “peroxycarboxylic acids” refer to a composition ormixture including more than one peroxycarboxylic acid, such as acomposition or mixture including peroxyacetic acid (PAA) andperoxyoctanoic acid (POOA).

“Objectionable odor,” “offensive odor,” or “malodor,” mean a sharp,pungent, or acrid odor or atmospheric environment from which a typicalperson withdraws if they are able to. Hedonic tone provides a measure ofthe degree to which an odor is pleasant or unpleasant. An “objectionableodor,” “offensive odor,” or “malodor” has an hedonic tone rating it asunpleasant as or more unpleasant than a solution of 5 wt-% acetic acid,propionic acid, butyric acid, or mixtures thereof.

“Peracid” or “Peroxy acid” refer to an acid having the hydrogen of thehydroxyl group replaced by a hydroxy group, oxidizing peracids arereferred to herein as peroxycarboxylic acids, peracids also includes theconjugate bases of peracids as well as those species that form in pHenvironments which alter the pKa of peracids.

“SRP” means sulfur-reducing prokaryotes which are organisms such asthose bacteria and archaea that can obtain energy by oxidizing orreducing organic compounds or molecular hydrogen (H₂) while oxidizing orreducing sulfur species (including but not limited to sulfates,thiosulfates, and elemental sulfur) often into to hydrogen sulfide(H₂S), by doing this SRP can “breathe” sulfur species rather thanoxygen, in a form of anaerobic respiration.

“PAA” means peroxyacetic acid a peroxycarboxylic acid with a chemicalformula of CH₃CO₃H, it is also known by such names as: acetic peroxide,acetyl hydroperoxide, proxitane, and ethaneperoxoic acid. It is oftenmade as an equilibrium product from the reaction between a peroxygensource with peracetic acid.

“PAA Demand” means the minimum dosage of PAA (and/or other peroxy acid)needed to kill substantially all microorganisms in a system, which aresusceptible to PAA biocide treatments as well as to completelystoichiometricaly react with all non-biological materials in the systemthat are oxidation-reduction reactive with peracids in the system suchas H₂S and FeS.

“Aerobic PAA Demand” means the minimum dosage of PAA (and/or otherperoxy acid) needed to kill substantially all aerobic microorganisms ina system that are susceptible to PAA biocide treatments.

“SRP PAA Demand” means the minimum dosage of PAA (and/or other peroxyacid) needed to kill substantially all SRP microorganisms in a system,which are susceptible to PAA biocide treatments.

“DMDS” means di-methyl di-sulfide, an organic disulfide compound havinga chemical formula of CH₃SSCH₃, it is flammable and has an unpleasantodor.

“Spectrometry” and “Spectroscopy” means the process of analyzing theinteraction between a sample of matter and electromagnetic radiation todetermine one or more physical properties of the sample of matter. Formsof electromagnetic radiation used include but are not limited to one ormore of microwave, terawave, infrared, near infrared, visible,ultraviolet, x-ray, radiation. The analysis includes measurements of oneor more of the radiation's absorption, emission, fluorescence,colorometrics, color changes, reflection, scattering, impedance,refraction, and resonance by the sample of matter.

In the event that the above definitions or a description statedelsewhere in this application is inconsistent with a meaning (explicitor implicit) which is commonly used, in a dictionary, or stated in asource incorporated by reference into this application, the applicationand the claim terms in particular are understood to be construedaccording to the definition or description in this application, and notaccording to the common definition, dictionary definition, or thedefinition that was incorporated by reference. In light of the above, inthe event that a term can only be understood if it is construed by adictionary, if the term is defined by the Kirk-Othmer Encyclopedia ofChemical Technology, 5th Edition, (2005), (Published by Wiley, John &Sons, Inc.) this definition shall control how the term is to be definedin the claims.

At least one embodiment of the invention is directed towards treating awater sample bearing SRP which is prone to releasing sulfide gas with anamount of PAA sufficient to substantially prevent the release of sulfidegas but insufficient to reduce the overall microbial population by morethan 60% and insufficient to reduce the mold population by more than10%. In at least one embodiment the method is to determine the aerobicPAA Demand of a system, to determine the SRP PAA Demand of a system andto apply a dosage of PAA to the system that is greater than the SRP PAADemand but less than the aerobic PAA Demand. Because of the greateroxidation-reduction potential of oxygen based metabolisms over sulfatebased metabolisms, many aerobic microorganisms are able to more quicklyproliferate and can more easily overcome treatment with a compound suchas PAA. In fact in some cases aerobic microorganism can reproduce at arate of every ˜20 minutes while SRP often only reproduce every ˜2.5-24hours. As a result, it is possible to apply PAA in a manner that willsubstantially sanitize a system of SRP and thereby eliminate the sulfideodor while allowing aerobic waste consuming organisms to survive.

In at least one embodiment one or more peracid bearing compositions areadded repeatedly over time to a water sample. Because in each case boththe SRP and aerobic microorganism populations are reduced by thecomposition but the aerobic microorganism population recovers so muchfaster, after enough additions the SRP population will be substantiallyeliminated. In at least one embodiment once eliminated, the dosage ofperacid needed to suppress a recurrence of SRP after it has beeneliminated is less that the initial SRP PAA demand and the dosage addedis less than the initial SRP PAA demand.

In at least one embodiment the peracid composition is added to thesystem according to a batch process. In at least one embodiment theperacid composition is added to the system according to a continuousprocess.

Compositions comprising one or more peracids such as PAA have been knownfor use as antimicrobials and bleaching agents. As such, while they havebeen used in odor control compositions before, their effectiveness inthis manner is quite unexpected. PAA is an oxidant in its own right andwill convert sulfide back into sulfate. As a result in low dosages, PAAwould be expected to make a water environment especially attractive toSRP as it tailors the oxygen supply to be more in their favor.

In addition, the use of low dosage PAA as an odor controller is theopposite of the teachings in the prior art. As described in US PublishedPatent Application 2010/0022644, PAA is well known as a highly effectivebiocide but it “suffer[s] from unacceptable odor” Id. As a result whenit is used to reduce odor it is part of a strategy of killing off muchor all of microorganisms present in an object and it requires theco-presence of an effective amount of an odor suppressant such as amineoxide to counteract the vinegar like odor associated with PAA. Thishowever would be ineffective in a situation such as waste water disposalin which the dosage needs to be less than that required to reduce themicrobial population of an object lest the water medium lose the abilityto degrade the organic material within the water. In at least oneembodiment the dosage of PAA added to the water is insufficient tosubstantially reduce the water's microbial population. In at least oneembodiment an effective amount of an odor suppressant such as but notlimited to amine oxide is excluded from being added to the water.

Similarly U.S. Pat. No. 6,015,536 discloses using PAA to reduce odors.There too however it is clear that the potency of PAA in killingmicrobial organisms is very pronounced. As a result it teaches that toreduce odors PAA is to be added to the gaseous effluent rather than thewater medium itself.

In at least one embodiment the Aerobic PAA Demand is determined by theuse of a color test. In a color test, equivalent proportions to between1-50 drops of starch indicator, weak acid, and potassium iodide areadded to a 10 ml sample of water, then sodium thiosulfate drops areadded one at a time until the sample turns colorless. The aerobic PAAdemand is then between 0.1 ppm to 50 ppm per drops needed to effect acolor change. Typically, the SRP PAA demand is between ⅕ to 1/100,000the aerobic PAA demand. As each wastewater system will have uniqueconditions based on the specific waste contents, amounts, and thespecific SRP and aerobic organisms therein, the SRP PAA demand andaerobic PAA demand can be unique for each system and in fact may changeover time. In at least one embodiment the SRP PAA demand and aerobic PAAdemand are measured over time and the amount of additive added ismodified to remain within the “in between” measurement.

In at least one embodiment an initial dosage is required to make thesystem inhospitable to SRP, but once that has been accomplished a muchlower dosage of additive is required to maintain the absence of SRP andthe dosages fed over time are modulated to reflect decreased PAA dosage.

In at least one embodiment different dosages of peracid compositions aremeasured to determine the specific population of aerobic and SRPpopulations before and after the addition of the composition. This canbe done to produce a function and/or curve indicating the SRP PAA demandand the aerobic PAA demand of the specific water system at a given time.In at least one embodiment the relative populations can be identifiedusing PCR, qPCR or any other equivalent method known in the art. In atleast one embodiment the measurement of one or more of the populationsbefore and/or after a sample or the water system itself is treatedaccording to one or more of those methods mentioned in U.S. patentapplication Ser. Nos. 14/138,526, 13/550,748 and 13/360,238.Measurements such as of total Bacteria, SRP and Archea per ml and qPCRwill further speciate and measure SRP per ml. Aliquots of the watersample can be dosed with different concentrations of peracidcompositions and the aforementioned testing can be performed on eachaliquot. In at least one embodiment the resulting product dosage versusTotal Bacteria Count and SRP count curve will allow administration ofproper product dosage to satisfy the SRP PAA demand while remaining wellbelow the aerobic PAA demand.

In at least one embodiment the aerobic PAA demand and the SRP PAA demandare determined using a culture-independent enumeration such asquantitative polymerase chain reaction (qPCR). This method allows forthe enumeration of specific organism groups (such as sulfate reducingbacteria and sulfate reducing archaea) as well as specific organismgenus or species. In short, this method works by collecting a sample,extracting the DNA from all microbes present, amplifying the microbialDNA via PCR, and quantifying the amount of DNA during each PCRamplification cycle by the incorporation of a fluorescing DNA-bindingdye. By determining up front the abundance of the aerobic and SRPpopulations, one can then determine how much peracid is required. Theperacid treatment should be sufficient to provide sufficient kill of theSRP population without killing too much of the aerobic population tocause negative impact on the wastewater process.

Referring now to FIG. 2 there is shown a graph of one such example. Ifwe assume that in a given system the aerobe population is 1,000,000 permL and the SRP population is 100,000 per mL and we perform a PAA demandstudy to understand the microbial kill efficiency we can then determinehow much PAA to add to minimize the SRP population without killing somany aerobes that it is detrimental to the waste water plant. This graphassumes that reduction after treatment may be something like: 50%reduction with a 20 ppm PAA treatment, 90% reduction with a 40 ppmtreatment, and 99% reduction with a 60 ppm treatment. The goal oftreatment would be to suppress the SPR population as much as possiblewhile still allowing a sufficient number of aerobes to survive and moveinto the waste process.

In at least one embodiment the peracid composition is added to a pointin the wastewater treatment system which is upstream from other furtherprocessing steps. In some subsequent steps excess (or substantially any)residual peracid may interfere with that processing, may damageequipment, or may cause unwanted side chemical reactions or may kill offother subsequent biological treatments. In at least one embodiment thelow dosage of peracid allows for the use of peracid to effectivelysuppress odor without so interfering with the subsequent waste treatmentsteps.

In at least one embodiment the composition contains species from bothsides of the equilibrium equation. In at least one embodiment the PAAcan be represented according to the structure:

PAA and other peracids often exist in an equilibrium state between anacid (such as acetic acid) and an oxygen donating species (such as aperoxide). The equilibrium at least in part may involve transitionbetween PAA, peroxide, and acetic acid, the relative amounts of PAA,peroxide, and acetic acid present in a given sample of equilibrium PAAmay vary based on the specific thermodynamic conditions of the givensample, at any given moment. Equilibrium PAA may comprise 0-100% PAA,0-100% peroxide, and 0-100% acetic acid, further details of equilibriumPAA and methods of its production are described in the paper: PeraceticAcid (CAS No. 79-21-0) and its Equilibrium Solutions, JACC No. 40, pp.2-3 (2013), and U.S. Pat. No. 7,012,154, as used herein “PAA” and“equilibrium PAA” also include all other per-acid biocides described inU.S. Pat. No. 7,012,154 mutatis mutandis.

PAA typically has a pKa of 8.2. In at least one embodiment the water theperacid composition is added to have a pH of between 6-10 preferably7-8.5. The peracid may exist in a protonated and/or a non-protonatedform. In at least on embodiment the peracid is added to the pHenvironment and/or is in one or more of the forms described in one ormore of U.S. Pat. Nos. 8,114,222 and 8,398,791.

There are a number of compositions and methods of their applicationrelevant to this invention. In at least one embodiment the low dosagecomposition is applied at a level above the SRP PAA demand level butbelow the aerobic PAA demand level. Such compositions may include one ormore of the chemicals and in particular the peracids and peroxy acidsmentioned in any one, some or all of US Published Patent Applications2012/0172439, 2012/0225943, 2012/0141407, U.S. patent application Ser.No. 11/847,604, and U.S. Pat. Nos. 7,160,712, 6,165,483, 7,816,555, and6,277,344. Representative examples of how such chemicals are producedand/or dispensed are also described therein.

In at least one embodiment the peracid composition is injected via apump into the water influent at a predetermined dosage based uponroutine microbial testing described above. Active PAA may be measured inthe water effluent to confirm that no active PAA is present whichindicates that aerobic PAA demand has not been achieved. If the water tobe treated is not flowing (holding pond or tank), the peracid may beinjected via pump or manually fed into the pond/tank to achieve thedesired dosage. In this case, peracid could also be injected via pumpinto a recirculating stream within the pond/tank to achieve the desireddosage.

Referring now to FIG. 3 there is shown at least one embodiment of theinvention which addresses the control of odor releases in water streams(such as wastewater) susceptible to nutrient shock/sugar shock. (As usedherein the terms “sugar shock” and “nutrient shock” are usedinterchangeably mutatis mutandis to describe the same fundamentalprincipal). As shown in the diagram if the process fluid undergoes anutrient shock (which could be in the form of a sudden jump in theconcentration of any microorganism sustaining nutrient and in particularincludes a sugar shock) after a particular time lag, in the face of aconstant odor control regime, there will often be a correspondingincrease in microorganism activity and therefore odor release. FIG. 3shows that in the absence of any anti-microbial regime, shortly afterthe shock occurs microbial populations rapidly increase and thereforecause a large increase in odor release.

Representative materials that would give rise to such a nutrient shockof course include sugar but also includes any organic compound(s) thatis biologically degradable and/or will provide a food source for odorcausing microbes to eat and multiply regardless of the presence orabsence of sugar. This includes but is not limited to any form of sugar,honey, sweetener, plant resin, plant syrup, molasses, glucose, mannose,galactose, proteins, meat, meat byproducts, dairy products, dairy waste,food waste, food byproducts, honey, carbohydrates, grains, grainstillage, corn, corn stillage, vegetable oils, fats, lipids, and anyfood, refined food, food derived byproduct, food derived waste product,and any combination thereof.

FIG. 3 also shows that in the face of an above described constant PAAregime targeted towards the expected steady state of the fluid prior tothe shock, after a larger time lag there too will occur an increase inthe microbial population. This will also result in a more potentmalodorous event.

In at least one embodiment a nutrient shock can be addressed byproportionally increasing the PAA content relative to the change inorganism population. Usually PAA preferentially reacts with H₂S/sulfidegenerated by the SRP microbes relative to microbes. As a result it willnormally have eliminated much of the H₂S/sulfide before having asignificant impact on the microbial population. Once the H₂S/sulfide hasbeen eliminated it can then go on to kill microbes until active PAA isno longer present. When microbial populations increase proportionatelywith the increased food source associated with the nutrient shock, aproportionate increase in PAA demand is required.

In at least one embedment a measurement of active PAA and PAA demand istaken. These measurements allow the operator to determine the extent ofthe population growth resulting from the nutrient shock and to increasethe increase in PAA enough to react to the shock but in a dosage suchthat no active PAA is available to be harmful to downstream receivers ofthis treated water.

In at least one embodiment a water flow is treated by an above PAAregimen but in the event of a nutrient/sugar shock, a large dose of mildFenton's Reagent is added to the system. Fenton's Reagent is a lessexpensive reactant for use against H₂S/sulfide than PAA. As a result bysupplementing the PAA with Fenton's Reagent, H₂S/sulfide levels can bereduced by the Fenton's Reagent which minimizes the reduction of PAA andtherefore frees up more PAA to kill SRP microbes. In at least oneembodiment the Fenton's Reagent is added in a dosage of between 0.001ppm and 1000 ppm.

In at least one embodiment the pH of the water being treated is between6.8 and 8.2. At this pH, Fenton's Reagent forms highly reactive hydroxylradicals which are effective at reducing microorganism activity. Whileit is known to use Fenton's Reagent in wastewater treatment it is oftendisfavored because the hydroxyl radicals are unstable so a dosage doesnot provide effective control for long (often as short as or shorterthan 12 hours). Worse it is largely ineffective against many forms ofbacteria, and it requires pH conditions which are often incompatiblewith the conditions in effect in many wastewater treatment facilitiesespecially treatment ponds. However in the context of a nutrient shock,because the Fenton's Reagent is only addressing a short term disruption,these limitations are actually beneficial attributes. (They can betargeted to the consequences of the shock, and when the shock ends, theyare no longer active). In this way the overall superiority of PAA overFenton's Reagent for sustained usage can be maintained, but in the eventof a sudden shock, Fenton's Reagent can be used in a manner more dynamicthan is optimal for PAA.

In at least one embodiment the PAA control regime is supplemented byFenton's Reagent in the event of a nutrient shock according to a feedforward strategy. In a feed forward strategy the system is constructedand arranged to anticipate a future nutrient shock and to feed theFenton's Reagent prior to the actual arrival of the increased amount ofsugar in the targeted water.

In at least one embodiment the PAA control regime is supplemented byFenton's Reagent in the event of a nutrient shock according to afeedback strategy. In a feedback strategy the system is constructed andarranged to detect the presence of a nutrient shock and to feed theFenton's Reagent in reaction to the detected increased amount of sugarin the targeted water. Either or both strategies may make use of any oneor more sorts of detectors which would indicate a nutrient shock.

In at least one embodiment a method is used to distinguish betweentypical “noise” inherent in the slight variations inherent in agenerally stable and a significant enough change that can becharacterized as a shock. This involves establishing upper and lowerbounds of measurements deemed acceptable. When a detected nutrientcontent is above the upper bounds it is no longer considered noise butconsidered a shock and the anti-shock treatment is implemented.Similarly the method may involve a sliding scale in which certainmeasurements are not considered shocks if their frequency of occurrenceis low enough but a sudden increase in frequency of such measurementswould be indicative of a nutrient shock. This methodology is applicableto any method of measuring the nutrient shock including but not limitedto those methods of measurement listed below.

In at least one embodiment the method of detecting the nutrient shockutilizes a spectroscopic detector method. A representative example ofspectroscopic detection is described in Patent Document WO 2012/054220A1. In at least one embodiment a nutrient shock is detected by measuringfluorescence in a fluid. In at least one embodiment the fluorescence ismeasured in one or more channels in response to an excitation lightsource at 320 nm and 409 nm and the measurement is correlated to aparticular amount of sugar in the fluid.

In at least one embodiment the method of detecting the nutrient shockutilizes an oxidation-reduction potential change in the fluid. Arepresentative example of oxidation-reduction potential change detectionof nutrients is described in U.S. Pat. No. 8,130,106.

In at least one embodiment the method of detecting the nutrient shockutilizes a nucleic acid measuring approach. Representative examples of anucleic acid measuring approach are described in U.S. Pat. No. 8,613,837and U.S. patent application Ser. No. 14/138,526. In at least oneembodiment the approach uses the nucleic acid measurement and/or adiversity index to determine a change in microbial distribution and/orpopulation and correlating that change with an increase in malodorousmicroorganisms.

In at least one embodiment the method of detecting the nutrient shockutilizes a sulfide or hydrogen sulfide detecting approach.Representative examples of a detecting sulfide or hydrogen sulfideinclude but are not limited to ASTM D4658, water measurements usingHatch starch/iodide tests, and air measurements using such apparatusesas Draeger tubes, Jerome meters, Odaloggers, and any combinationthereof.

The use of such detector(s) can facilitate either or both of a feedforward and/or feedback approach. In a feed forwards strategy thedetector can be located at position(s) upstream from the location wherethe odor control regime is being implemented indicating an impedingshock. They can also be set up to detect the loss of these materialselsewhere indicating a leak which will contaminate the influent to thelocation where the odor control regime is being implemented. In afeedback strategy the detector can be located at position(s) at ordownstream from the location where the odor control regime is beingimplemented indicating an ongoing or previous shock. Both feedback andfeed forward strategies may use detectors that allow for the remediationof an odor event before it becomes detectable to human senses.

In at least one embodiment the detector is positioned to measure thepresence of a shock in evaporator condensate. In at least one embodimentthe evaporator condensate is from a sugar mill.

At least one embodiment of the invention is a method and/or an apparatusfor predicting/detecting and/or addressing an odor spike due to anutrient shock in a water system. This comprises fluidly coupling adetector, a first feeding mechanism, and a second feeding mechanism to aprocess water stream, the detector constructed and arranged to detectthe amount of nutrient in the water and to transmit information thereofto a controller device, the first feeding mechanism constructed andarranged to optionally and in variable measurements feed PAA into thewater stream, the second feeding mechanism constructed and arranged tooptionally and in variable measurements feed Fenton's Reagent into thewater stream; the controller device configured to recognize thecharacteristics of a nutrient shock, and to automatically provideoperational instructions to the second feeding mechanism based on thosecharacteristics.

In at least one embodiment the controller contains informationcorresponding to an excess of nutrient content in the water and whensupplied information from the detector it uses process logic which isconstructed and arranged to cause/allow/induce the introduction ofFenton's Reagent into the water.

The controller may also be constructed and arranged to containinformation corresponding to desired properties of the water includingbut not limited to pH, desired concentrations of PAA, Fenton's Reagent,nutrients, and/or any other material present or possibly present in thewater.

At least one embodiment further comprises a Nutrient detector, PAAdetector, and/or a Fenton's Reagent detector. One or more of thedetectors supplies information to one or more controllers which suitablyincreases, decreases, and/or ceases the flow of PAA, Fenton's Reagent,and or one or more reagents suitable to neutralize PAA and or Fenton'sReagent so as to alter the water's properties to correspond with desiredproperties.

In at least one embodiment the controller is constructed and arranged toreceive new/changed information regarding the desired characteristics ofthe water and it alters its response to detected water properties tocorrespond in accordance with the new/changed information.

EXAMPLES

The foregoing may be better understood by reference to the followingexamples, which are presented for purposes of illustration and are notintended to limit the scope of the invention.

A bench test was performed on various samples of sulfide ladenwastewater taken from a covered pond at a food processing plant. Thesamples were allowed to sit for various periods of time and were treatedwith one of: nothing, a commercial odor suppressant (8314 sold by NalcoCompany, Naperville, Ill.), and a PAA product (REDOXX 60 sold by EcolabUSA, St. Paul, Minn.). The effectiveness of these additives was measuredover the time relative to when the additives were added by using a HatchDR-890 sulfide meter to measure the sulfide ppm in the treated samplesversus sulfide ppm in the untreated sample. As demonstrated in Table 1,at high dosages over long periods of time, both REDOXX and thecommercial odor suppressant reduced sulfide level. However of the two,only REDOXX was effective at significantly reducing sulfide at lowdosages over long periods of time. Sulfide measurement has proven to bemore accurate than measurement of hydrogen sulfide in the vapor spaceabove the water sample (which is readily diluted with the atmosphere).We know that less sulfide means less hydrogen sulfide gas/malodor.

TABLE 1 Total Sulfides Time Elapsed Additive Measured Percent(hours:minutes) (dosage in mg/l) (mg/l) reduction %  9:45 — 0.33 —  9:45commercial 10 0.25 24%  9:45 REDOXX 10 0.25 24% 13:40 — 1.6 — 13:40commercial 10 1.04 35% 13:40 REDOXX 10 0.62 61% 13:40 commercial 20 0.3280% 13:40 REDOXX 20 0.16 90% 16:25 — 4.6 — 16:25 commercial 10 2.16 53%16:25 REDOXX 10 1.25 72% 16:25 commercial 20 0.96 79% 16:25 REDOXX 200.32 93%

Without being limited by a particular theory or design of the inventionor of the scope afforded in construing the claims, it is believed thatthe peracid substantially eliminated the SRP population at low dosagesso it was effective at low dosages. In contrast the commercialquaternary ammonium odor suppressant only worked on the sulfides afterthe SRPs produced them so over time as the SRP population increased, thecommercial product was less effective. This can be seen in Table 2 whichcompares the overall populations of microorganisms measured with PCRwithin samples after various additives have been present for periods oftime.

TABLE 2 Additive Time Elapsed Name Total bacteria Bacteria % SRBsArchaea Archaea % (hours) (amount) per mL** change per mL per mL change0 Commercial 5,680,630,503 — <LOD* 98,612 — 1200 ppm 4 Commercial13,835,308,772 +160% <LOD* 103,101  +4% 1200 ppm 0 REDOXX 6021,120,497,248 — <LOD* 1,170,753 — 1000 ppm 3.5 REDOXX 60 1,079,650,145 −95% <LOD* 19,915 −99% 1000 ppm *Below the detection limit of the assay

Table 2 demonstrates that the peracid and the commercial odorsuppressant operate very differently. Over time in the presence of thecommercial product, there is exponential growth of bacteria whilearchaea population remains stable. This indicates that it is doingnothing to the underlying microbial population and is merelycompensating for the actions of the SRP. In contrast the peracid treatedsample drastically undergoes a reduction in the populations of botharchaea and bacteria but at different rates. This indicates that peracidcan be dosed to preferentially target one organism (such as SRP) whilenot eliminating another organism (such as waste consuming organisms).

This principle can be seen in FIG. 1. There it is shown that the releaseof DMDS sulfide gas is relative to the bacteria population not the moldpopulation. (SRP are rarely if ever molds but many bacteria are SRP). Asa result, adding a PAA dosage that drastically eliminates bacteria butis substantially harmless to molds will effect a large reduction in odorrelease.

Table 3 provides an illustration of fine tuning a peracid dosagerelative to PAA demand. In this table it was pre-determined that overallperacid demand for the specific sample was 600 ppm. As increasingdosages of peracid are added the overall active ATP count will dropbecause it is imposing ever harsher conditions. These conditions howeveraffect various organisms differently and can be used to determine a SRPPAA demand which is lower than the aerobic PAA demand.

TABLE 3 Peracid Total Active added (ppm) ATP % Reduction 0 3181 — 602145 32.6% 90 1581 50.3% 120 965 69.7% 600 —  100%

While this invention may be embodied in many different forms, there aredescribed in detail herein specific preferred embodiments of theinvention. The present disclosure is an exemplification of theprinciples of the invention and is not intended to limit the inventionto the particular embodiments illustrated. All patents, patentapplications, scientific papers, and any other referenced materialsmentioned herein are incorporated by reference in their entirety.Furthermore, the invention encompasses any possible combination of someor all of the various embodiments mentioned herein, described hereinand/or incorporated herein. In addition the invention encompasses anypossible combination that also specifically excludes any one or some ofthe various embodiments mentioned herein, described herein and/orincorporated herein.

The above disclosure is intended to be illustrative and not exhaustive.This description will suggest many variations and alternatives to one ofordinary skill in this art. All these alternatives and variations areintended to be included within the scope of the claims where the term“comprising” means “including, but not limited to”. Those familiar withthe art may recognize other equivalents to the specific embodimentsdescribed herein which equivalents are also intended to be encompassedby the claims.

All ranges and parameters disclosed herein are understood to encompassany and all subranges subsumed therein, and every number between theendpoints. For example, a stated range of “1 to 10” should be consideredto include any and all subranges between (and inclusive of) the minimumvalue of 1 and the maximum value of 10; that is, all subranges beginningwith a minimum value of 1 or more, (e.g. 1 to 6.1), and ending with amaximum value of 10 or less, (e.g. 2.3 to 9.4, 3 to 8, 4 to 7), andfinally to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 containedwithin the range. All percentages, ratios and proportions herein are byvolume unless otherwise specified.

This completes the description of the preferred and alternateembodiments of the invention. Those skilled in the art may recognizeother equivalents to the specific embodiment described herein whichequivalents are intended to be encompassed by the claims attachedhereto.

The invention claimed is:
 1. A method of reducing the odor released by awastewater treatment system while preserving the vitality ofwastewater-treating and waste-consuming microorganisms within thesystem, the method comprising the steps of: continuously adding to aprocess flow of water a composition in an amount such that it is inexcess of the SRP PAA demand but is below the aerobic PAA demand,detecting a sudden surge in nutrient content in the process flow ofwater, in response to the detected surge adding an effective amount ofFenton's Reagent to the flow, wherein the composition comprises at leastone peroxy acid.
 2. The method of claim 1 in which the Fenton's Reagentis added before there is a detectable change in the population ofmicroorganisms in the wastewater treatment system.
 3. The method ofclaim 1 in which the Fenton's Reagent is added before the nutrient surgereaches the wastewater treatment system.
 4. The method of claim 1 inwhich the Fenton's Reagent is added after there is a noticeable increasein odor.
 5. The method of claim 1 in which the amount of continuouslyadded composition is not altered in response to the sudden surge innutrient content.
 6. The method of claim 1 in which the surge innutrient content is detected by measuring fluorescence from thenutrient.
 7. The method of claim 1 in which the surge in nutrientcontent is detected by measuring fluorescence from the nutrient inresponse to a first excitation light source having a wavelength of 320nm and a second excitation light source having a wavelength of 406 nm.8. The method of claim 1 in which the nutrient is one or more sugars. 9.The method of claim 1 in which the process flow is condensate from aboiler in a sugar mill.
 10. The method of claim 1 wherein thecomposition eliminates at least one biofilm layer on at least onesurface of the wastewater treatment system and the lack of said biofilmlayer prevents the localization against that surface of at least one of:H₂S, a biogenic acid, a corrosive biogenic material, and any combinationthereof.
 11. The method of claim 1 wherein the composition comprisesPAA.
 12. The method of claim 1 wherein the composition is added in anamount lower than a quaternary ammonium odor suppressant but is morethan 10% effective than said quaternary ammonium odor suppressant wouldbe at suppressing sulfide odor release.
 13. The method of claim 1wherein the aerobic PAA demand of the system is determined by measuringthe minimum ppm amount of composition that needs to be added to causesubstantially no less than a 98% drop in total active ATP in thewastewater.
 14. The method of claim 1 excluding the presence of an odorsuppressing co-ingredient which neutralizes the innate odor of theperoxy acid.
 15. The method of claim 1 in which the composition is feddirectly into a portion of the wastewater system selected from the groupconsisting of: a wastewater pond, an EQ tank, a wastewater storage tank,and any combination thereof.
 16. The method of claim 1 in which thecomposition is fed directly into one item selected from the groupconsisting of: a trunk line which feeds wastewater into a storagevessel, a stationary water system, a recirculating water system, and anycombination thereof.
 17. The method of claim 1 in which the compositionis fed directly into a covered pond and the composition reduces theamount of sulfide acid corrosion by more than 10% than if thecomposition were not added to the pond.
 18. The method of claim 1 inwhich the composition reduces oxygen demand of the wastewater.
 19. Themethod of claim 1 in which the peracid is a reaction product between aperoxygen source other than hydrogen peroxide with a peracetic acid.